This section provides background information related to the present disclosure, which is not necessarily prior art.
Fuel delivery systems of direct injected engines often include a high-pressure fuel pump for pumping fuel to a first fuel rail and a second fuel rail. The fuel rails deliver fuel to a plurality of fuel injectors associated therewith. The fuel rails are often connected to the high-pressure pump with a Y-block, or a cross-over line extending between the fuel rails so as to connect the fuel rails in “series.” To attenuate fuel pulsations, orifices are added to fuel feed lines that deliver fuel to the fuel rails, and a pressure relief path to a fuel pump chamber is included. In spite of the orifices and the relief valve, fuel pulsations from one fuel rail often affect the pressure in the other fuel rail. For example, if a three lobe pump cam is used, there will be one pumping event for every two consecutive injection events (occurring on opposite fuel rails). This often leads to a pressure differential between the fuel rails, which is undesirable.
A fuel delivery system that provides pressure relief and isolates fuel rails from one another such that there is no pressure differential between them would therefore be desirable. This permits reduction in both fuel rail volume and pressure rise times. Isolating the fuel rails also reduces the number of joints between the high-pressure pump and the fuel rails, which simplifies assembly and reduces both assembly time and cost.